Radial artery

The radial artery (Latin: arteria radialis) is one of the major blood vessels in the forearm. It is one of the terminal branches of the brachial artery, arising from its bifurcation on the anterior aspect of the elbow. The other terminal branch is the ulnar artery, which is the largest of the two.

This blood vessel travels down the lateral (or radial) aspect of the forearm, reaching the wrist where it branches into smaller branches to supply the hand.

The pulse of the radial artery is palpable at the wrist, which is used routinely to determine the heart rate.

Course

The radial artery arises from the bifurcation of the brachial artery (a continuation of the axillary artery) at the lower portion of the cubital fossa. However, it appears to be the continuation of the brachial artery, although it is smaller than the ulnar artery, which is the second branch arising from the bifurcation.

In the forearm, the radial artery travels down from the medial side of the neck of the radius to reach the styloid process of the anterior side of the radius. Proximally, the radial artery is situated deep to the brachioradialis muscle, while distally, it is covered only by a fascia and the skin. Therefore it is possible to palpate the pulse when the artery is pressed against the bone. In the forearm, the artery runs along two radial veins and the superficial branch of the radial nerve.

The artery reaches the styloid process of the radius and passes to the dorsal side of the wrist, where it lies in the “anatomical snuff box” that is limited by the tendons of abductor pollicis longus and extensor pollicis brevis muscles from the one side and the tendon of the extensor pollicis longus from the other side. The radial artery penetrates the first interosseous space between the first and second metacarpal bone and the dorsal interosseous muscle here, reaching the palmar side of the hand.

Branches

Many branches arise from the radial artery - in the forearm, wrist, and hand, including the following:

• radial recurrent artery - originates at the cubital fossa area laterally from the radial artery, runs down the lateral aspect of the forearm and forms anastomosis with the radial collateral artery from the deep brachial artery;
• muscular branches - supply the anterior and lateral muscle groups of the forearm;
• superficial palmar branch - arises from the radial artery at the level of the styloid process of the radius, on the palmar side of the wrist it gives off branches to supply the lateral muscle group of the hand and the skin over them; it forms an anastomosis with the terminal branch of the ulnar artery to form the superficial palmar arch;
• palmar carpal branch - arises from the radial artery at the distal part of the forearm; it forms an anastomosis with the palmar carpal branch of the ulnar artery, together creating an arterial network;
• dorsal carpal branch - originates from the radial artery at the dorsal side of the wrist; it forms an anastomosis with the carpal dorsal branch of the ulnar artery, together creating an arterial network;
• first dorsal metacarpal artery - arises from the radial artery at the dorsal aspect of the wrist in the “anatomical snuff box,” where it gives off three branches to supply the dorsal side of the index finger from the radial side and the thumb;
• princeps pollicis artery - a branch of the radial artery that arises from the palmar side of the wrist, giving off two branches to supply the palmar side of the thumb;
• radialis indicis artery - another branch of the radial artery arising from the palmar side of the wrist, which runs along the distal end of the index finger, supplying its lateral (radial) side. 

The radial artery terminates on the palmar side of the hand as the deep palmar arch and forms anastomosis with the deep palmar branch of the ulnar artery.